This invention relates to a remote terminal for data communication systems. More particularly the invention is concerned with remote terminal apparatus for use in connection with a coaxial cable television signal distribution system.
In cable television systems, data signals and television program signals are communicated between a central data processing system and a plurality of remote data terminals each at a subscriber's location. Typically, the terminals provide security monitoring functions by generating status and alarm data to be directed to the central processing system over coaxial cable or by other communication means. In controlling security operations, such terminals typically monitor and report on the status of various alarm indicators including those for fire, medical emergency, intrusion, assault, supervisor fault, tamper and battery low condition. In the cable television program mode, the terminals enable remote television units to receive and descramble television program data from a central television network upon proper authorization from the central processing system for the subscriber. The terminals also can be designed to provide data to the central processing system concerning the selected TV receiver channel and the status of the TV reception.
In the last few years, many new applications have become feasible for cable television systems requiring more sophisticated and efficient systems and system components than previously available. New data processing systems have been developed as disclosed in our co-pending patent application Ser. No. 40,446 (nonessential subject matter) to accommodate these new applications and to provide general purpose data acquisition and control functions in addition to security and pay television operations. This expanded variety of cable usage requires terminal development beyond past passive systems which only monitor security and TV sensors and provide whatever information is requested from the central processing system. Such conventional terminal units do not have the efficiency necessary to be compatible with these more sophisticated data communications systems and to provide the data processing functions needed to free the central processing systems for overall management functions.